Here's a breakdown:

* Elements: An element is a pure substance made up of only one type of atom. For example, gold (Au) is an element made up entirely of gold atoms.

* Compounds: A compound is formed when two or more different elements chemically combine in a fixed ratio. For example, water (H₂O) is a compound made of two hydrogen atoms and one oxygen atom.

Atoms themselves are composed of three main types of subatomic particles:

* Protons: Positively charged particles found in the nucleus of an atom. The number of protons determines the element.

* Neutrons: Neutral particles also found in the nucleus. Neutrons contribute to an atom's mass but don't affect its charge.

* Electrons: Negatively charged particles that orbit the nucleus in specific energy levels called electron shells. Electrons are responsible for chemical bonding and interactions between atoms.

Key Points

* Elements are the simplest forms of matter and cannot be broken down into simpler substances by chemical means.

* Compounds are formed when two or more elements chemically combine in a fixed ratio, creating a new substance with properties different from its constituent elements.

* Atoms are the building blocks of elements and compounds, and they are made up of protons, neutrons, and electrons.

Let me know if you have any other questions!